<template>
  <!--放大镜-->
  <div class="spec-preview">
    <!--左边主图-->
    <img :src="imgObj.imgUrl" />
    <div class="event" @mousemove="handler"></div>
    <div class="big">
      <!--右侧放大镜图片-->
      <img :src="imgObj.imgUrl" ref="big"/>
    </div>
    <!--遮罩层-->
    <div class="mask" ref="mask"></div>
  </div>
</template>

<script>
 export default {
  name: "Zoom",
  props: ['skuImageList'],
  data() {
    return {
      currentIndex: 0,
      
    };
  },
  mounted() {
    // 在组件挂载后立即设置事件监听器

    this.$bus.$on('getIndex', (index) => {
    
      this.currentIndex = index;
      this.imgObj = this.skuImageList[this.currentIndex] || {};
    });
  },
  beforeDestroy() {
    // 在组件销毁前移除事件监听器，防止内存泄漏
    this.$bus.$off('getIndex');
  },   computed: {
      imgObj() {
        return this.skuImageList[this.currentIndex] || {};
      }
    },
    methods: {
      handler(event) {
       // 获取遮罩层
       let mask = this.$refs.mask;
       let big = this.$refs.big
       //左边距=鼠标x距离-遮罩层宽度的一半
       let left = event.offsetX - mask.offsetWidth / 2; 
       let top = event.offsetY - mask.offsetHeight / 2;
       //修改元素top以及left值
       //约束范围
       if (left <= 0) left = 0;
       if (left > mask.offsetWidth) left = mask.offsetWidth;
       if (top < 0) top = 0;
      if (top > mask.offsetHeight) top = mask.offsetHeight;
      //修改元素的位置
      mask.style.left = left + 'px';
      mask.style.top = top + 'px';
//放大倍数
      big.style.left = -2 * left + 'px';
      big.style.top = -2 * top + 'px';

  }
}
  }
</script>

<style lang="less">
  .spec-preview {
    position: relative;
    width: 400px;
    height: 400px;
    border: 1px solid #ccc;

    img {
      width: 100%;
      height: 100%;
    }

    .event {
      width: 100%;
      height: 100%;
      position: absolute;
      top: 0;
      left: 0;
      z-index: 998;
    }

    .mask {
      width: 50%;
      height: 50%;
      background-color: rgba(0, 255, 0, 0.3);
      position: absolute;
      left: 0;
      top: 0;
      display: none;
    }

    .big {
      width: 100%;
      height: 100%;
      position: absolute;
      top: -1px;
      left: 100%;
      border: 1px solid #aaa;
      overflow: hidden;
      z-index: 998;
      display: none;
      background: white;

      img {
        width: 200%;
        max-width: 200%;
        height: 200%;
        position: absolute;
        left: 0;
        top: 0;
      }
    }

    .event:hover~.mask,
    .event:hover~.big {
      display: block;
    }
  }
</style>